Formation of ordered surface phases in submonolayer B/Si(110) and (Al, B)/Si(110) systems

The B/Si(110) system with B coverages below 0.1 ML has been studied by LEED-AES (low energy electron diffraction-Auger electron spectroscopy). The ($\text{10}\text{0}\text{− 2}\text{1}$) reconstruction has been found to form at above 0.07 ML of B. This reconstruction is a particular case of a more general type of superstructures with basic translation vectors, $\text{a}{}_{\mathrm{s}}\text{=(n/2[1}\text{1}\text{10]}$ and $\text{b}{}_{\mathrm{s}}\text{=[1}\text{1}\text{11]}$. Reconstructions of this type are observed for a number of adsorbates (Ge, AL, Sb) on the Si(110) surface. The factor n equals 8, 9 and 14 for Ge/Si(110), Al/Si(110) and Sb/Si(110) reconstructions, respectively. For the B/Si(110) reconstruction n = 10, but ordering along the [$\text{1}$10] direction is not perfect while the periodicity along the [1$\text{1}$1] direction is well-defined. The deposition of 0.05 to 0.15 ML of Al onto the B/Si(110) surface produces a well-ordered structure of the above-described type with n = 12. The deposited Al atoms replace the B atoms reducing the boron surface concentration.